Correct specification of tableauArg and tableauReturn

[Dan-C-Reed]

Say I have an R function that I wish to turn into an API for Tableau and I'd like to use this (awesome!) package. My function doesn't require any arguments and returns a data frame that contains a variety of types. A toy example is included below.

library(plumber)
library(plumbertableau)

#* @apiTitle An example
#* @apiDescription Simple example function
#* @tableauArg x:[logical] A dummy variable
#* @tableauReturn [integer] Returning some stuff
#* @post /mtcars
function(x) {
  mtcars[1:3, ]
}

# The Plumber router modifier tableau_extension is required
#* @plumber
tableau_extension

When I run this API (through Swagger), I get the following:

  {
    "mpg": 21,
    "cyl": 6,
    "disp": 160,
    "hp": 110,
    "drat": 3.9,
    "wt": 2.62,
    "qsec": 16.46,
    "vs": 0,
    "am": 1,
    "gear": 4,
    "carb": 4,
    "_row": "Mazda RX4"
  },
  {
    "mpg": 21,
    "cyl": 6,
    "disp": 160,
    "hp": 110,
    "drat": 3.9,
    "wt": 2.875,
    "qsec": 17.02,
    "vs": 0,
    "am": 1,
    "gear": 4,
    "carb": 4,
    "_row": "Mazda RX4 Wag"
  },
  {
    "mpg": 22.8,
    "cyl": 4,
    "disp": 108,
    "hp": 93,
    "drat": 3.85,
    "wt": 2.32,
    "qsec": 18.61,
    "vs": 1,
    "am": 1,
    "gear": 4,
    "carb": 1,
    "_row": "Datsun 710"
  }
]

This is exactly what I want. Fantastic!

Question 1

Note that I have included tableauArg despite my function not needing any arguments. If I omit this and the argument to my function, I get the following:

Error: Tableau argument and return data types must be specified.

Is there a correct way to omit arguments if they are not needed or do I always have to include a dummy argument like above?

Question 2

Similarly, I must include a data type for tableauReturn. I specify that the return type is an integer, but actually the data frame includes a mixture of integers, doubles, and strings. In Swagger, at least, the response above looks good. How should I specify mixed response data types, like shown in the above example?

Any help would be greatly appreciated and kudos on a stellar package!

---

Edit:

To follow up on Question 2: it looks like this specifies the SCRIPT_* function that Tableau uses (e.g., SCRIPT_INT in the example above since I specify @tableauReturn [integer]). Given that this is how Tableau and plumbertableau interact, presumably there's no way around this besides returning all data as strings (SCRIPT_STR) and doing the type conversion in Tableau?